etrn(1M)						  System Administration Commands						  etrn(1M)

NAME

       etrn - start mail queue run

SYNOPSIS

       etrn [-b] [-v] server-host [client-hosts]

DESCRIPTION

       SMTP's  ETRN  command  allows an SMTP client and server to interact, giving the server an opportunity to start the processing of its queues
       for messages to go to a given host. This is meant to be used in start-up conditions, as well as for mail nodes that have transient  connec-
       tions to their service providers.

       The etrn utility initiates an SMTP session with the host server-host and sends one or more ETRN commands as follows: If no client-hosts are
       specified, etrn looks up every host name for which sendmail(1M) accepts email and, for each name, sends an ETRN command with that  name	as
       the argument. If any client-hosts are specified, etrn uses each of these as arguments for successive ETRN commands.

OPTIONS

       The following options are supported:

       -b	       System boot special case. Make sure localhost is accepting SMTP connections before initiating the SMTP session with server-
		       host.

		       This option is useful because it prevents race  conditions  between  sendmail(1M)  accepting  connections  and  server-host
		       attempting to deliver queued mail. This check is performed automatically if no client-hosts are specified.

       -v	       The  normal mode of operation for etrn is to do all of its work silently. The -v option makes it verbose, which causes etrn
		       to display its conversations with the remote SMTP server.

ENVIRONMENT VARIABLES

       No environment variables are used. However, at system start-up, svc:/network/smtp:sendmail reads /etc/default/sendmail. In  this  file,	if
       the variable ETRN_HOSTS is set, svc:/network/smtp:sendmail parses this variable and invokes etrn appropriately. ETRN_HOSTS should be of the
       form:

       "s1:c1.1,c1.2	    s2:c2.1 s3:c3.1,c3.2,c3.3"

       That is, white-space separated groups of server:client where client can be one or more comma-separated names. The :client part is optional.
       server is the name of the server to prod; a mail queue run is requested for each client name. This is comparable to running:

       /usr/lib/sendmail -qR client

       on the host server.

EXAMPLES

       Example 1: Using etrn

       Inserting the line:

       ETRN_HOSTS="s1.domain.com:clnt.domain.com s2.domain.com:clnt.domain.com"

       in  /etc/default/sendmail  results  in  svc:/network/smtp:sendmail invoking etrn such that ETRN commands are sent to both s1.domain.com and
       s2.domain.com, with both having clnt.domain.com as the ETRN argument.

       The line:

       ETRN_HOSTS="server.domain.com:client1.domain.com,client2.domain.com"

       results in two ETRN commands being sent to server.domain.com, one with  the  argument  client1.domain.com,  the	other  with  the  argument
       client2.domain.com.

       The line:

       ETRN_HOSTS="server1.domain.com server2.domain.com"

       results in set of a ETRN commands being sent to both server1.domain.com and server2.domain.com; each set contains one ETRN command for each
       host name for which sendmail(1M) accepts email, with that host name as the argument.

FILES

       /etc/mail/sendmail.cf	       sendmail configuration file

       /etc/default/sendmail	       Variables used by svc:/network/smtp:sendmail

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWsndmu 		   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Stable			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       sendmail(1M), attributes(5)

       RFC 1985

NOTES

       Not all SMTP servers support ETRN.

SunOS 5.10							    10 Aug 2004 							  etrn(1M)